Grease gun



G. C. SMITH GREASE GUN Sept. 10, 1935.

Filed Dec. 17, 1954 INVENTOI; Grover a mzfl/ AT RNEY Patented Sept. 1Q, 1935 ETED 15 Claims.

This invention is an improved grease gun of the type shown in the Sjogren, United States Letters Patent No. 1,605,475, which shows a screw actuated piston working in a charge barrel or container to discharge grease into the chamber of an associated pressure booster device including a lever operated plunger.

An object of this invention is to eliminate the screw-action piston in the barrel and employ in its stead an automatic, spring motivated piston with means for its ready and reliable energization subsequent to the retraction of the piston in the charge barrel for filling purposes. In this connection it is an object to provide a handle means for effecting the piston retraction and provide for substantially concealing an elongated element of the handle means in the barrel after it has been loaded and its actuating spring has been energized.

An object is to provide a motivating spring device of such construction and arrangement and combination that as the piston is retracted for loading the barrel the spring element will follow out with the piston handle and oifer no resistance to the retraction of the piston, and further an object is to provide for the compression of the spring, for action against the piston, by and with the relatively free inward and concealing movement of the handle device. And, in this relation, an object is to provide a manually controlled latch means for holding the spring in compressed, actuating state and for releasing the spring so that it may follow out with the piston pulling stroke of the handle.

An additional object is to provide means for packing the piston on the relatively slidable rod member of the handle device.

A desideratum is to provide a grease gun of this type in which the booster chamber is provided with a laterally extending cap into which the adjacent end of the charge barrel is adapted to be screwed after the barrel has been filled at its open end while detached from the relative booster, and a feature of the present invention is the provision of means to facilitate the entry of the barrel end into the booster cap threads and to then function as a supporting shoulder or bench to materially relieve the screw threads of the cap of heavy stresses during the action of the manual lever of the booster plunger when ejecting grease therefrom.

The invention consists of certain advancements in this art as set forth in the ensuing disclosure and having, with the above, additional objects and advantages as hereinafter developed, and

whose construction, combination and details of means, and the manner of operation will be made manifest in the description of the herewith illustrative embodiment; it being understood that modifications, variations and adaptations may be resorted to within the scope, principle and spirit of the invention as it is more directly claimed hereinafter.

Figure l is a sectional elevation of the gun showing the piston in loaded condition of the i9 barrel and the power spring as compressed for action on the piston; the piston rod being in restored or concealed position in the barrel after spring compressing or inward stroke.

Figure 2 is a sectional detail showing the released spring as being pulled outward from the barrel with the piston rod.

Figure 3 is a sectional detail showing the packing of the piston on its rod.

Figure 4 is an inside face view of the head member of the barrel, and

Figure 5 is an outside face View thereof; showing in section the housing of the spring controlling latch device.

Figure dis a perspective of the control latch.

The gun includes a charge barrel 2 of suitable size and any desired material having fixed on one end a head 3 having a central hole "3 surrounded externally by a hub 5 having a tangential housing 6f Turnably mounted in the housing is a latch-forming pin 7' recessed at 8 and having a short, lateral born 9 at its upper end forming a handle by which the latch may be turned so as to present the recess 8 toward the hub hole 4 to form an' uninterrupted continuation thereof. The latch is normally turned so that its side obstructs the hole 3 by means of a spring H! attached thereto and having an end anchored in the breather hole i I of the barrel head 3.

The head holed is of a size to slidably receive 49 a tubular abutment or collar i2 having a peripheral groove i3 complementary to the body of the latch i so as to automatically lock therewith in the position shown in Fig. 5, and to disengage when the latch is turned to present its recess 8 in register with the hole. The abutment I2 is slidably mounted on a stifirod I 4 having a'handle l5 on its outer end and having on its inner end a nut or other shoulder l6 whereby to engage a piston structure and retract it as the handle rod 5 is pulled'outward from the barrel head 3.

The piston structure includes back-to-back cups ll of suitable material clamped between discs l8 mounted on a central sleeve l9 slidably fitting on the'rod ltand bored to receive a, packing gland 26 which slides in the sleeve and fits the rod H.

To efiect the automatic discharge action of the piston l'i and its advance along the barrel 2 there is interposed between the piston gland 2D and the abutment I2 an expansion spring 2! which is of a size to slide outward in the head hole A with the handle rod i4 when the abutment l2 has been released from its holding latch 1.

The retractive movement of the piston i'i by the hand rod H! is stopped by means of a light tube 22 loosely enclosing the spring and forming a spacer between the head 3 and the piston at its retracted position as shown in 1.

When the piston is in the retracted position the barrel 2 is then loaded with grease through its open, threaded end 3 and this is then screwed into a complementary cap 25 which extends laterally at a right angle from the side of a small muzzle or chamber 28 bored from end to end and having a packing gland 21 in its rear end and through which works a plunger rod 28. The outer end of the plunger is pivotally connected to a hand lever 25? fulcrumed on a link 30 which is pivoted at 3| on the rear end of the chamber 2t. The lever 29 is provided with a lug 32 in which the pivot 33 of the link 30 is disposed and the lug presents a face 34 toward the plunger 28 to engage it and form a lever stop device and also take shearing stress off of the link pivot 38.

It is very desirable that a direct passage be provided from the barrel cap 25 to the booster chamber 26 and this is accomplished by a short, straight, lateral duct 35 from the center of the cap to a point in the bore of the chamber as just in advance of the retracted position, Fig. 1, of the booster plunger 28. This provides for instant flow of the grease, under pressure of the spring actuated piston H, to the booster chamber 26 whose discharge end has a small check valve 36 opening outwardly but seating with sufiicient pressure to prevent continuous discharge under piston action while the plunger is back to open the duct 35.

The booster chamber thus contains a measured charge and this is discharged under great pressure when the plunger is forced into the chamber by handle 29.

The rear end of the booster chamber is provided with a side wall shoulder or bench 3! disposed at the open, threaded side of the barrel cap 25 and forms a restand guide for the open end of the barrel as this is screwed into the cap after the barrel has been loaded. After the barrel is so screwed into the cap the bench is in such close contiguity to the barrel that as the plunger handle is moved on discharging stroke the barrel and the bench engage each other and the working strains are materially removed from the threads of the cap and barrel end; it being understood that the barrel is held in one hand while the plunger lever is operated by the other hand of the user of the gun.

The operation is as follows: to load the gun the barrel is easily unscrewed from the cap 25 and the open end of the gun is immersed in a batch of grease and the barrel is held in one hand while with the other hand the handle rod M of piston I! is pulled out as a finger of the hand is placed on the latch horn 9 and by this the latch i is turned, against the holding action of its spring I (i, to register the recess 8 with the bore of the hub 5 and thus release the spring abutment [2 allowing this to move out through the head 3 as the piston rod I 4 is drawn out to retract the piston and induct grease into the barrel. The floating spacer sleeve or tube 22 stops the piston at the outward limit and then the handle or piston rod is pressed inwardly and slides freely through the piston sleeve l9 while the piston is supported on the charge in the gun; the barrel 2 having been screwed into the cap 25 before the handlerod is forced in.

As the piston rod [4 is pressed inwardly' the spring 2| slides through the head hub 5 and piles up pressure on the blocked piston I? as the abut ment i2 moves toward the latch I which, in its ment groove and therefore interlocks the abutment and holds the main spring 2| compressed and motivative on the piston, regardless of the relatively free, inwardly pressed and concealed piston rod It in the barrel. It will be seen that the main spring is energized by the inward movement of the handled, piston rod M, and will be effective until the full .oharge is spent from the barrel, by successive operations of thebooster lever in the usual manner while the nozzle of the booster chamber is applied to the part to be greased.

What is claimed is:

1. In a gun of the class described, a charge barrel having a head, a piston fitting in the barrel, a piston rod slidably connected to the piston, a spring surrounding the rod and reacting at one end on the piston, an abutment slidably mounted on the rod and against which the spring reacts, means including a trip latch engaging the abutment and looking it to the head, and means attached to said rod for pulling it and the spring outwardly through the head with the unlocked abutment and whereby the rod is pushed inwardly through the locked abutment and through said piston when this is arrested by a gun charge.

2. In a gun of the class described, a charge barrel having a head, a rod and a spring mounted thereon, a piston slidably mounted on the inner end of the rod and working in the barrel, an abutment slidably mounted on the other end of the rod and between which abutment and the piston the spring is compressed, said abutment slidably fitting in the head, a trip device for locking the abutment to the head, the spring acting between the locked abutment and the piston to force the latter against the gun charge, and a handle attached to the rod and whereby it and the spring are pulled out through the head with the abutment when the latter is released from said device, and whereby the rod is pushed inwardly through the head to compress the spring against the piston.

3. In a gun of the class described, a charge barrel having a head on one end, a piston working in the barrel, a rod for pulling the piston back, and a spring device engaged and compressively energized by inward movement of the rod to place the piston under discharge pressure; said rod and spring being operatively mounted in the head; said rod having a spring abutment slidably mounted thereon, and a manually releasable, self acting latch on the head to engage and interlock the abutment with the head.

4. In a gun of the class described, a charge barrel having a head, a piston working in the barrel, means working through the head to retract the piston for loading the barrel, a spring retractive by said means without increased pressure on the piston and which is engaged and energized by said means upon inward movement of the latter, and a spring latch to interlock said head and said means and thereby hold the spring compresse the said means including a rod which is slidable freely in the piston while the latch is efiective on said means.

5. In a gun of the class described, a charge barrel, a piston working in the barrel, means for retracting the piston for loading the barrel, and a spring motivating the piston and which is bodily retractive through a head of the barrel without increase of pressure on the piston as this is retracted and which is compressed by an inward action of said means for effort on the piston; said means including a rod slidable inwardly through the piston and having a sliding abutment for the spring, a locking means on the head to interlock with the abutment; said rod and abutment being slidable outwardly from the head when the abutment is unlocked therefrom.

6. In a gun of the class described, a charge barrel, a piston working in the barrel, a handled piston rod for retracting the piston to load the barrel and slidable freely inwardly through the piston, a spring mounted on the rod and bodily retractive therewith through the head of a barrel without increase of pressure on the piston as this is retracted and which is compressed by inward action of the rod, and means for holding the spring under compression and including a spring latch mounted on said head and an abutment for the spring slidably mounted on the rod and movable therewith outwardly from the head and interlockable in inner position at the head by said latch.

7. In a gun of the class described, a charge barrel, a piston working in the barrel, a handled piston rod freely slidable in the piston and operative to retract it for loading the barrel, a spring mounted on the rod and reactive on the iston and retractive without increase of pressure on the piston, said rod operative. independent or" the piston to compress the spring for reaction on the piston, and means for holding the spring under compression against the piston independently of the rod; the barrel having a head, and said means including a spring seat slidably mounted on the rod and retractive outwardly therewith as to the head and a manually releaseable, spring latch for interlocking said seat with the said head.

8. In a gun of the class described, a charge barrel, 2. piston working in the barrel, a piston rod slidably associated with the piston and manually operative to retract the piston for loading the barrel, an abutment slidably mounted on the rod, a spring on the rod and normally reacting between the piston and the abutment and being bodily retractive by the rod zith the piston without pressure accumulation and being compressible by inward movement of the rod, and means to interlock with the abutment and hold the spring under compression and permitting free inward movement of the rod as to the locked abutment and as to the piston, for discharging action on the piston; said interlocking means including a spring latch which is tripped by the inwardly moving abutment to interlock therewith and which is manually operable to release the abut- 5 ment for retractive movement of the piston, the spring and the rod.

9. In a gun of the class described, a piston rod,

a piston slidably mounted on the rod, and a main spring; said piston having a central packing sleeve and relatively slidable gland therein slidably fitting the rod and against which said spring reacts in motivating the piston.

10. In a gun of the class described, a barrel head, a rod slidable in the head, a piston in which the rod is slidable, and a spring confined on the rod between the said piston and a part on the rod and slidable outwardly through the head with the rod; the spring being compressed against the piston by and with inward movement of the rod, and a manually releaseable, self-acting means engageable with the said part for locking the spring in compressed state when the rod is pressed inward through the head.

11. A grease gun including a charge barrel having a movable piston, a spring reacting on the piston, and a rod sliding through the head of the barrel and operative in one direction to engage and retract the piston and in the other to engage and compress the spring, and locking means against which the said spring reacts and which is operative to hold it in compressed state for discharge effort on the piston; said rod being slidably mounted in and freely movable in either direction as to the piston and the locked spring. 5

12. A grease gun having a barrel head, a rod slidable through the head and having a piston slidable thereon, a spring reactive on the piston, means movably mounted on and with the rod and forming a seat for the spring, means for 0 locking the last named means to the head to hold the spring compressed; said rod being freely movable as to the piston while the spring is locked and active to shift the piston along the rod.

13. A grease gun having a rod, a piston slidable on the rod, a spring coiled on the rod and reacting on the piston, an abutment slidably mounted on the rod and supporting the spring, and a locking means through which the rod and the spring are slidable and which interlocks with said abutment when the rod is pushed inward to increase pressure of the spring on the piston.

14. A device as in claim 13 and in which the rod is freely shiftable as to the piston and the abutment while the latter is locked.

15. A grease gun having a barrel with a head,

a rod slidable in and out through the head, a piston working in the barrel, and a spring confined on the rod and reactive on the piston; said 0 rod operative on its outward stroke to engage and retract the piston in the barrel and thereby to draw the spring out through the head and on its inward stroke to move freely through the piston and compress the spring back into the 5 barrel.

G-ROVER C. SMITH. 

